Achieving shared protection for dynamic multicast sessions in survivable mesh WDM networks

The advances in wavelength-division multiplexing (WDM) technology are expected to facilitate bandwidth-intensive multicast applications. A single fiber failure in such a network, however, can disrupt the information dissemination to several destination nodes in a "light-tree"-based multicast session. Thus it is imperative to protect the multicast sessions. In this paper, we propose a novel protection scheme, called multicast protection through spanning paths (MPSP), for resource efficient multicast protection with spare capacity sharing. Here, a spanning path is a path from a leaf node to any other leaf node of a multicast tree. The key idea of MPSP is first to identify a backup path for each spanning path and then to appropriately select parts of these backup paths to protect the primary multicast tree, so that the total bandwidth allocated to the primary multicast tree and its protection paths (or trees, etc.) is minimized. While previous studies only consider self-sharing and intra-request sharing, to the best of our knowledge, this is the first time to take inter-request sharing of spare capacity into consideration when protecting dynamic multicast sessions. We use simulations to demonstrate the performance of the MPSP scheme. It is shown that significant performance improvements are achieved in terms of average cost per multicast session and blocking probability. Compared with existing schemes, the average cost is reduced by about 22% and the blocking probability can be reduced by about 27% in average.